feat(typescript-estree): handle 3.9's non-null assertion changes #2036
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[TS 3.9 introduced a breaking change for how non-null assertions are handled in optional chains](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-9.html#parsing-differences-in-optional-chaining-and-non-null-assertions). Pre-3.9, `x?.y!.z` means `(x?.y).z` - i.e. it essentially scrubbed the optionality from the chain Post-3.9, `x?.y!.z` means `x?.y!.z` - i.e. it just asserts that the property `y` is non-null, not the result of `x?.y` This PR: **updates the AST so it matches this** Previously `x?.y!.z` produced `MemberExpression > TSNonNullAssertion > OptionalMemberExpression`. Now it produces `OptionalMemberExpression > TSNonNullAssertion > OptionalMemberExpression`. Note that `(x?.y)!.z` still produces `MemberExpression > TSNonNullAssertion > OptionalMemberExpression`. Same results apply for call expressions. **updates `no-non-null-asserted-optional-chain` to handle this** With the above AST change, the only change needed was a simple "is parent optional chain" check. Both of these changes are gated behind a version check, so they are completely backwards compatible.
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Codecov Report
@@ Coverage Diff @@
## master #2036 +/- ##
==========================================
- Coverage 93.91% 93.68% -0.24%
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Files 172 172
Lines 7843 7871 +28
Branches 2253 2263 +10
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+ Hits 7366 7374 +8
- Misses 217 233 +16
- Partials 260 264 +4
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TS 3.9 introduced a breaking change for how non-null assertions are handled in optional chains.
Pre-3.9,
x?.y!.zmeans(x?.y).z- i.e. it essentially scrubbed the optionality from the chainPost-3.9,
x?.y!.zmeansx?.y!.z- i.e. it just asserts that the propertyyis non-null, not the result ofx?.yThis PR:
updates the AST so it matches this
Previously
x?.y!.zproducedMemberExpression > TSNonNullAssertion > OptionalMemberExpression.Now it produces
OptionalMemberExpression > TSNonNullAssertion > OptionalMemberExpression.Note that both
(x?.y)!.zand(x?.y!).zstill produceMemberExpression > TSNonNullAssertion > OptionalMemberExpression.Same results apply for call expressions.
updates
no-non-null-asserted-optional-chainto handle thisWith the above AST change, the only change needed was a simple "is parent optional chain" check.
Both of these changes are gated behind a version check, so they are completely backwards compatible.
Fixes #1976